1.Fly the aircraft at a cruise power setting between 65 and 75 percent power, as specified in the aircraft Pilots Operating Handbook/Aircraft Flight Manual (POH/AFM), for a duration that will allow the engine oil and cylinder head temperatures to stabilize, or at least 45 minutes. Perform an additional differential compression test on the suspect cylinder(s).
2. A sudden increase in oil consumption from the established or normal trend for the engine or an oil consumption rate that exceeds 1/2 quart (liter) per hour during normal engine operation.